Downhole equipment such as packers are essential components in the suite of well completion equipment required for production or injection wells. Unfortunately, defects within the packer's sealing element can cause failure of the packer with catastrophic consequences for the well's safe operation or its productivity. To date, conventional non-destructive inspection techniques have been applied in an attempt to discover such defects.
Conventional non-destructive inspection has consisted of techniques such as visual inspection, ultrasonic inspection, Laser, holographic and other optical methods, mechanical test methods and combinations of these methods, such as those used in automobile or airplane tire safety inspection. Each of these methods has severe drawbacks. For example, visual inspection does not reveal defects below the surface. Likewise, ultrasonic inspection does not provide sufficient spatial resolution required to observe the defect in detail. Additionally, with regard to ultrasonic inspection, rubber compounds, elastomeric and composite materials are well known acoustic absorbers thereby limiting the depth of ultrasonic wave penetration.
There exists, therefore, a need for non-destructive inspection techniques that enable detection of internal and external defects in downhole components such as packers. Such defects include de-laminations, de-bonds, and other defects in materials such as rubbers, elastomers, fiber reinforced composites, graphite composites, fiberglass, metal, and rubber/metal parts.